within these genes that have observed P-values <0.05 (e.g. DRD1 and DRD2) in the current study, none of these genes have SNPs with significantly adjusted P-values. Furthermore, none of the reported SNPs are significant in the current study (see Supplementary Material, Tables S1 and S2 for complete results). While this may be owing to the difference in phenotypes, confirmation of results by further studies is the key to valid conclusions in this area of research (57). In addition, systems-based analyses may be performed, which more formally integrates prior knowledge via ontologies into the identification and testing of relevant associations (58–61).
